OLED Pixel Structure with Reflective Concave Cavity for Light Extraction
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Solution Overview
Problem
Current organic light-emitting diode (OLED) displays, particularly active-matrix OLEDs, face challenges in achieving high energy efficiency due to poor light extraction, which is essential for reducing power consumption and enhancing display performance, as existing light out-coupling techniques often degrade image quality, are complex to fabricate, and not compatible with top-emitting OLED structures.
Innovation Solution
A three-dimensional optically reflective concave structure within the OLED pixel, filled with a high-index filler material, is used to enhance light extraction efficiency by redirecting internally generated photons for external coupling, while maintaining image quality and scalability across various pixel colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional light out-coupling techniques (microlens arrays, surface textures, scattering media) are used to enhance light extraction, then light extraction efficiency is improved, but image quality deteriorates due to pixel blurring and light leakage to neighboring pixels
Solution Approach 1:
The invention segments the pixel structure by introducing a three-dimensional concave configuration with reflective surfaces that are spatially confined within each pixel boundary. This segmentation prevents light from one pixel from leaking into neighboring pixels, thereby maintaining image quality while enhancing light extraction efficiency through the reflective concave structure.
Solution Approach 2:
The invention applies local quality by creating a specialized three-dimensional concave reflective structure only within the pixel region where light extraction enhancement is needed. The reflective surfaces are positioned and configured locally to redirect light internally generated photons without affecting the optical properties of surrounding areas, thus improving light extraction while preserving image quality.
2Loss of energy
If advanced optical out-coupling structures (high-resolution nano-fabrication) are implemented, then light extraction efficiency is improved, but fabrication complexity increases and integration compatibility decreases
Solution Approach 1:
The invention employs a three-dimensional concave reflective structure with curved surfaces that can be fabricated using standard semiconductor processing techniques. The curvature of the concave structure is designed to optimize light reflection and extraction without requiring advanced nano-fabrication, thereby reducing fabrication complexity while maintaining high light extraction efficiency.
Solution Approach 2:
The invention transitions from two-dimensional planar structures to a three-dimensional concave configuration. This dimensional change enables effective light extraction enhancement through reflective surfaces that redirect light in multiple directions, achieving high extraction efficiency without the need for complex nano-scale patterning, thus simplifying fabrication and improving integration compatibility.
3Loss of energy
If existing out-coupling methods are used, then some light extraction enhancement is achieved, but extraction efficiency remains limited and is strongly wavelength and viewing-angle sensitive
Solution Approach 1:
The three-dimensional concave reflective structure serves multiple functions: it enhances light extraction efficiency, maintains image quality by preventing pixel blurring, and achieves wavelength-insensitive performance. The reflective surfaces are configured to redirect light effectively across different wavelengths and viewing angles, making the structure universally applicable without strong sensitivity to these parameters.
Solution Approach 2:
The invention optimizes the geometric parameters of the three-dimensional concave structure, including the depth, angle, and surface configuration of the reflective surfaces. By carefully adjusting these parameters, the structure achieves high light extraction efficiency that is insensitive to wavelength and viewing angle variations, thereby improving adaptability and versatility across different operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach achieves high light extraction efficiency of approximately 80% and maintains excellent viewing characteristics, making it suitable for high-resolution full-color displays without significant wavelength sensitivity or fabrication complexity, thereby addressing the limitations of existing methods.
Implementation Method 1
filled with a high-index filler material, is used to enhance light extraction efficiency by redirecting internally generated photons for external coupling
Implementation Method 2
A three-dimensional optically reflective concave structure within the OLED pixel, filled with a high-index filler material, is used to enhance light extraction efficiency by redirecting internally generated photons for external coupling
Implementation Method 3
A three-dimensional optically reflective concave structure within the OLED pixel, filled with a high-index filler material, is used to enhance light extraction efficiency by redirecting internally generated photons for external coupling
Data Source
AI summary
The present invention discloses a general, highly effective and scalable extraction-enhancing OLED display pixel structure based on embedding the OLED inside a three-dimensional reflective concave structure selectively filled with a high-index filler material. Such a structure is able to couple as much as possible internally generated photons into the filler region and then redirect otherwise confined light for out-coupling via the reflective concave structure. Ultimately high light extraction efficiency approaching ˜80% and excellent viewing characteristics are simultaneously achievable with optimized structures using highly transparent top electrodes. This scheme is scalable and wavelength insensitive, and thus can be generally applied to all red, green, and blue pixel OLEDs in high-resolution full-color displays.